1. Field of the Invention
The present invention relates to an information recording-displaying card capable of displaying visibly and rewriting information by heating, an over sheet used for the information recording-displaying card, an image processing method, an image processor, and a method of manufacturing the information recording-displaying card.
2. Description of the Related Art
Information recording card such as a membership card, an ID card, a credit card, a cash card, an IC card and the like partly has an information storing section such as a magnetic tape, an IC chip and the like. This information storing section can record an individual secret information, especially such as money and the like. Due to its compactness and convenience, the information recording card is widespread in many countries in modern society. The information recording card carries out reading and rewriting of the recorded information with a special unit, although leaving a shortcoming that the card owner cannot visually (directly) verify the recorded information.
On the other hand, developed and used recently in the market is a rewritable card capable of carrying out a temporary image forming, and capable of erasing the image when the image is not necessary. More specifically, the above rewritable card is the one that can visually display the information on its surface and can rewrite the information. Some rewritable cards are provided with a magnetic information storing function.
The above function of the rewritable card, namely, displaying visually and rewriting the information as an image can be expressed by forming the following states: Between an electron-donating compound (so-called a leuco dye) and an acid/base compound, a coloring state and a decolorizing state are relatively formed with a difference in one of the following: i) a heating temperature, and ii) a cooling rate after a heating. Hereinabove, the electron-donating compound has a lactone ring in its molecular structure and may assume the coloring by making a structural change attributable to the lactone ring opened by an electron discharge, while the acid/base compound functions as a developing-reducing reagent. For example, Japanese Patent Application Laid-Open (JP-A) No. 2-188293 and JP-A No. 2-188294 disclose a rewritable card made of a reversible recording material having such a structure that a reversible thermosensitive recording layer is disposed on a support. Herein, a resin base material for the reversible thermosensitive recording layer contains, as main materials thereof, the electron-donating compound and the developing-reducing reagent which are described above. More specifically, the above reversible thermosensitive recording material uses a difference in reaction rate between the acid and the base, to thereby repeat the colorings and the decolorizings.
JP-A No. 5-124360 and JP-A No. 6-210954 disclose a reversible thermosensitive recording material having a resin base material containing i) a leuco dye and ii) an electron-accepting compound having a long-chain alkyl group as a developing agent. The developing agent with the long-chain alkyl structure has a cohesive force, and contacts the leuco dye or is separated from the leuco dye, thus repeating the colorings and decolorizings.
Since sufficiently compensating for the conventional shortcoming of the information recording card described above, the reversible thermosensitive recording material having the functions of displaying visually and rewriting the information attracts attention. With this, such a card is developed and recently begins to be used in the market as has a first function (as an image displaying section) of displaying visually and rewriting information and a second function (as an information storing section) of recording and rewriting the information. Hereinafter, the above card is to be referred to as “information recording-displaying card.”
The above information recording-displaying card, basically, uses i) an over sheet such as a reversible thermosensitive recording material in which at least a reversible thermosensitive recording layer is disposed on a support, and ii) a core sheet having a function as the conventional information recording card. The above information recording-displaying card can be formed by overlapping the over sheet's support side with the core sheet, followed by a thermo-compression bonding and the like.
The image displaying function of the above information recording-displaying card is carried out by the over sheet. On the other hand, the image storing function of the above information recording-displaying card may vary with types of the card. More specifically about this: The information storing function by a magnetic material such as a magnetic tape can be carried out by the over sheet or the core sheet. However, the information storing function by an IC chip, antenna coil, a magnetic stripe and the like is, in general, disposed in a thick core sheet.
Some information recording-displaying cards are thin and others are thick. Since the over sheet is thin, the thickness of the information recording-displaying card is ordinarily dependent on the thickness of the core sheet.
The information recording-displaying card recently beginning to be used in the market is made of a combination of the following i) and ii): i) a reversible thermosensitive over sheet using, as a support, a polyethylene terephthalate (PET) film, and ii) a core sheet having, as a raw material, polyvinyl chloride (PVC) resin, polyvinyl chloride resin such as copolymer of vinyl chloride and vinyl acetate, or polycarbonate resin.
The above materials are widely used for the following reasons: The polyethylene terephthalate (PET) film used for the support of the over sheet is highly resistant to a solution which is made by dissolving a composition (especially, constituting the reversible recording layer) in a solvent. The polyvinyl chloride (PVC) resin used as the core sheet material is excellent in physical property, mechanical property, embossability (at character section), and the like.
The above polyvinyl chloride resin is also proper as the support of the over sheet, so as to obtain an image eraseability, in view of expressing, to a certain extent, a flexibility by heat.
Though being excellent as the card's raw material, the above polyvinyl chloride may, from some viewpoints, cause a hydrogen chloride gas when incinerated after being used and then scrapped, thus damaging an incinerator and reducing lifetime thereof.
Mover, movement of eliminating the polyvinyl chloride (PVC) resin is becoming more and more active in various countries, although relation between the polyvinyl chloride (PVC) and dioxine is not clarified. The polyvinyl chloride resin is used for the information recording-displaying card as well as the conventional information recording card, in other words, has high publicity. With the above background, other material replaceable with the polyvinyl chloride (PVC) is desired also domestically.
For use as the raw material for the information recording-displaying card, a thermoplastic resin is being studied that does not contain halogen. Examples of the above thermoplastic resin include polyethylene resin, polypropyrene resin, polyester resin, polycarbonate resin, polyacrylic resin, and the like.
Among the above, the card's base material made of polycarbonate resin and the like is highly resistant to heat, thereby, is unlikely to cause deformation attributable to heat, becoming an excellent material in terms of durability. The information recording-displaying card using the polycarbonate resin and the like is, therefore, appearing in the market.
However, being low in deformability, the polycarbonate resin is low in embossability. The reversible thermosensitive recording material for writing-erasing by using a thermal head may lose head matching property with the thermal head contacting the information recording-displaying card, thus reducing sensitivity, leading especially to deteriorated eraseability, which is a shortcoming. A raw material replaceable with the polyvinyl chloride resin is conventionally not found.
On the other hand, a unity which is the over sheet bonded with the core sheet is to be embossed. The thus formed “emboss marking” is to be marked on the information recording-displaying card, to thereby make personal information identifiable, which is important in terms of convenience and usefulness. Especially, a thick card such as the credit card, the bank card and the like is to be provided with the “emboss marking,” which is indispensable in the modern society. In sum, the embossing is more and more required from users and various industries.
The above “emboss marking” is mainly used for card number, expiration, owner's name and the like, and has such a function as to be copied with a roller, by interposing the card into a copy voucher for reckoning at a store and the like. The above use of the “emboss marking” is prevalent domestically and overseas.
The polyethylene terephthalate (PET) film used for the support of the over sheet is so rigid as to have low deformation by an applied pressure, thereby, has an extremely low embossability. With this, even when the polyvinyl chloride resin used for the core sheet has a good embossability and the embossing is carried out from upside of the over sheet, the over sheet using the polyethylene terephthalate (PET) film may cause an insufficient “emboss marking.” Moreover, the polyethylene terephthalate (PET) film becoming too thick may cause breaking of the card in the embossing.
Especially, a thick card with the above non-contact IC chip, antenna coil, magnetic stripe and the like embedded therein cannot sufficiently absorb irregularity thereof, thereby making it impossible to flatten the card's surface. With this, the above thick card cannot smoothly carry out rewriting of the recording by the thermal head and the like, therefore, as the case may be, forcibly increases printing pressure and temperature. As a result, the above thick card may have failures such as having scratches, having remaining gouge, causing deformation, and the like, thus limiting application and manufacturing methods, and thereby finding difficulty in using manufacturing steps of the general-purpose card.
The information recording-displaying card which is recently beginning to be used in the market has the following structure. The embossing is carried out in an embossable space formed on the core sheet's surface which space is free from the over sheet. In this structure, the over sheet bonded to the core sheet is smaller in size than the core sheet's surface. The above over sheet is to be bonded to the core sheet such that the “emboss marking” can be disposed in the embossable space free from the over sheet.
The above method is limited in terms of manufacturing since, for example, the over sheet reduced in size is to be accurately bonded to the core sheet, moreover, the above method is limited in terms of an area for the over sheet's image display function, which are shortcomings.
In sum, the embossing cannot be carried out for a unity having the over sheet bonded to the entire face of the core sheet, making an information recording-displaying card without the “emboss marking.”
The reversible thermosensitive recording material used as the over sheet is “thermosensitive” which is a special material. In each of the steps including i) overlapping the over sheet (having the above special property) on the core sheet, ii) uniting the over sheet with the core sheet by pressing-heating, and iii) completing the embossing, it may be difficult to manufacture the information recording-displaying card without influencing the above special property, namely, “reversible thermosensitivity.”
Moreover, the polyethylene terephthalate film used as the support of the over sheet is made of a material which is higher in heat resistance and smaller in heat deformation than the polycarbonate resin. Therefore, applying a thermal head as a heating unit to a surface of the above over sheet of the information recording-displaying card beginning to be used in the market may cause very little deformation by the heat. This may make the adhesion between the thermal head's face and the over sheer's surface insufficient, thus losing head matching at the heat application and thereby decreasing the sensitivity. With this, especially the eraseability may become low, namely, an insufficient image eraseability is caused, which is a shortcoming.
The present inventors have studied the known data related to the above type of the information recording-displaying card, as a result, to find that any of the known data are free from description of the embossability, and image eraseability involved with the embossability.
Described below are specific examples of the information recording-displaying cards disclosed in cited patent documents.
Firstly, for example, JP-A No. 2001-341427 (page 2 to page 4, example 1) discloses an over sheet which is a reversible recording film having the following structure. A print layer, a transparent support having light transmission of 50% or more, a reversible recording layer, and a protective layer are disposed on a support. A thick information recording-displaying card is disclosed having the support side united with a core sheet by using an adhesive. However, JP-A No. 2001-341427 (page 2 to page 4, example 1) does not describe embossability at all.
Material usable for the above support and the above transparent support are described (likewise between the two) as follows: “a plastic film is applicable thereto which is rigid, namely, excellent in heat resistance, tensile strength and the like,” and “selectable thickness in a range from 8.5 μm to 300 μm, preferably 8.5 μm to about 250 μm.” Specific examples of the material include polyethylene terephthalate (PET) film, polyethylene naphthalate (PEN) film, polyimide (PI) film, polyphenylene sulfide (PPS) film, and the like. Moreover, the transparent support is made of materials such as vinyl chloride film, PET-G film, and polycarbonate and the like.
JP-A No. 2001-341427 (page 2 to page 4, example 1) describes that the above films exemplified are made of plastic which is rigid, namely, excellent in tensile strength and the like. In view of embossability, however, JP-A No. 2001-341427 (page 2 to page 4, example 1) includes those evidently not embossable, judging from the description of an unrigid film and too rigid a film, and the description of a small thermal deformation and a large thermal deformation.
In view of thickness, an example 1 in JP-A No. 2001-341427 (page 2 to page 4, example 1) does not describe thickness of polyethylene terephthalate film used as the support but describes that the transparent support uses a transparent polyethylene terephthalate film having thickness of 25 μm, which is too thick for the embossing of the over sheet.
Moreover, the over sheet itself that is formed according to this example 1 of JP-A No. 2001-341427 (page 2 to page 4, example 1) has the polyethylene terephthalate film as the support and as the transparent support, thus losing the head matching at the heat application and thereby decreasing the sensitivity. With this, especially the image eraseability may become low.
As a core sheet material, JP-A No. 2001-341427 (page 2 to page 4, example 1) describes examples including vinyl chloride resin, PET-G typical of polyester resin, polycarbonate resin, which are used alone or in combination. No description of the embossability in JP-A No. 2001-341427 (page 2 to page 4, example 1) proves impossibility of the embossing.
For the next example, JP-A No. 2000-137782 (example 1 and example 2) discloses a card's base material (core sheet) which is a thermoplastic resin sheet having low crystal property of 5% or less. A thick information recording-displaying card is disclosed which is a unity of the above card's base material (core sheet) bonded with a reversible thermosensitive recording tape (over sheet). The reversible thermosensitive recording tape hereinabove is provided with a reversible thermosensitive recording layer (containing a leuco compound and a developing agent) on a transparent PET film.
JP-A No. 2000-137782 (example 1 and example 2) is, however, free from any description of embossing. Judging from the thick PET film (25 μm in thickness in an example 1, and 38 μm thick in an example 2), the information recording-displaying card is not embossable and has a poor eraseability.
For the next example, JP-A No. 11-154210 (example) discloses i) a sheet (core sheet) incorporating therein an IC chip module, and ii) a reversible thermosensitive recording sheet (over sheet) provided with a reversible thermosensitive recording layer (containing a leuco dye and a developing agent) on a film, which two sheets are opposed to each other. To a gap between the core sheet and the over sheet, a resin is injected and thereby the two sheets are bonded with each other, thus forming an IC card (thick information recording-displaying card). However, JP-A No. 11-154210 (example) is free from any description of embossing.
For the next example, JP-A No. 2001-88443 (example) discloses a recording medium used for mass production adopting a Kanban (signboard) method, which recording medium has a base material, a reversible thermosensitive recording layer (containing a leuco compound and a developing agent) on the base material, and a protective layer. Various types of plastic films are exemplified as the base material. A white PET which is the base material in each example has a thickness of 188 μm, 250 μm and 350 μm, proving no attention is paid to embossing.
JP-A No. 2000-137782 (example 1 and example 2), JP-A No. 11-154210 (example) and JP-A No. 2001-88443 (example) described above disclose various specific examples of materials for the support constituting the over sheet, and materials for raw materials constituting the core sheet. In view of the embossing, like JP-A No. 2001-341427 (page 2 to page 4, example 1), some materials thus exemplified may cause a small thermal deformation and other materials thus exemplified may cause a large thermal deformation, i.e., including those embossable and not embossable.
Summarizing the above, the information recording-displaying card beginning to be used in the market is not embossable on the over sheet's face. For the embossing, therefore, the image display area is reduced, making the image eraseability insufficient and causing environmental pollution in the scrapping and disposal.
The information recording-displaying card disclosed in the known data is not studied in view of the embossing or the image eraseability involved with the embossability. Moreover, no proposal is made in the above known data for solving the environmental pollution in the scrapping and disposal.
For bringing about a sufficient embossability to the information recording-displaying card, each of the over sheet and the core sheet constituting the information recording-displaying card, and the unity of the over sheet and the core sheet are to have the embossability. The conventionally known product and the conventionally known data are free from the above viewpoint.
By patent documents and the like, various proposals are conventionally made in terms of the reversible thermosensitive recording material. The embossability is, however, not suggested or raised at all in the above patent documents and the like. Not to mention, the embossability of an over sheet of an information recording-displaying card is not suggested or raised at all. In sum, securing embossability in this technical field and improving the image eraseability involved with the embossability are new issues.
In terms of the embossability, for example, JP-A No. 11-240262 (claims) discloses a heated transfer card having an acceptor layer disposed on a card's base material. More specifically, a dye in JP-A No. 11-240262 (claims) is contained in a heat transfer film in the field of heating-melting transfer recording or a sublimating transfer recording, instead of the reversible thermosensitive recording. The dye is to be melted or sublimated by a heat, and then is received or fixed by the acceptor layer.
The proposal in JP-A No. 11-240262 (claims) uses a special polyester for the card's base material, and a polyester copolymer is used for the acceptor layer which copolymer is made by copolymerizing a reactive silicone polymer. With the above, the moldability such as embossability of the heated transfer card is improved. As a matter of course, however, no description is made of accomplishment of the embossability without influencing the special property (namely, “reversible thermosensitivity”) which is the image eraseability of the over sheet.
By patent documents and the like, many proposals are conventionally made in terms of the reversible thermosensitive recording material. The embossability is, however, not suggested or raised at all in the above patent documents and the like. Not to mention, the embossability of an over sheet of an information recording-displaying card is not suggested or raised at all. In sum, securing the embossability in this technical field and improving the repetition durability involved with the embossability are new issues.
Objects and Advantages
It is an object of the present invention to provide an information recording-displaying card that is excellent in embossability and displayed-image eraseability, easy to scrap and dispose, and is free from causing an environmental pollution in the scrapping and disposal. It is anther object of the present invention to provide an image processing method and an image processor for forming an image and erasing the image by using an over sheet and the information recording-displaying card each of which is made of a reversible thermosensitive recording material that is excellent in embossability and displayed-image eraseability. It is still another object of the present invention to provide a method of manufacturing the information recording-displaying card.